The synthesis of citrulline from arginine in the small intestine depends on the provision of ornithine. To test the hypothesis that arginase II plays a central role in the supply of ornithine for citrulline synthesis, the contribution of dietary arginine, glutamine, and proline was determined by utilizing multitracer stable isotope protocols in arginase II knockout (AII(-/-)) and wild-type (WT)...

1. During the normal development of the rat, the specific activity of liver ornithine-keto acid aminotransferase exhibits a transient elevation around term, and subsequently increases to adult activity levels during the third postnatal week. 2. The synthetic glucocorticoid triamcinolone, administered as a single injection, produces a marked elevation of the ornithine-keto acid aminotransferase ...

During the life cycle of Chlorella vulgaris Beijerinck var vulgaris fa. vulgaris growing synchronously, the specific activity of ornithine decarboxylase peaked at the 2nd hour of the cycle, whereas that of arginine decarboxylase changed only slightly, increasing towards the end of the cycle. The endogenous level of putrescine and spermidine on a per cell basis increased gradually up to the 8th ...

Treatment of male mice with excess androgens increased the activity of renal ornithine decarboxylase 60-fold in the BALB/c strain and 4-fold in the CD-1 strain. Part of the increase in the activity of ornithine decarboxylase was due to a decreased rate of degradation of the enzyme since activity declined more slowly (t1/2 80 min) in androgen-treated BALB/c mice than in controls (t1/2 20 min) wh...

Human ornithine transcarbamylase is a trimer with 46% amino acid sequence homology to the catalytic subunit of E coli aspartate transcarbamylase. Secondary structure predictions, distributions of hydrophilic and hydrophobic regions, and the pattern of conserved residues suggest that the three dimensional structures of the two proteins are likely to be similar. A three dimensional model of ornit...

PathoTec strips and spot biochemical tests were evaluated for the ability to biotype Haemophilus influenzae and Haemophilus parainfluenzae. Indole, urease, and ornithine decarboxylase reactions were tested. The results of PathoTec strips compared favorably with those conventional methods; the percent agreements were as follows: indole, 100; urease, 99.5; and ornithine, 95.5. Spot tests were sim...

Mice with the X-chromosomal sparse-fur (spf) mutation frequently have urinary bladder stones composed mostly of orotic acid, which was identified by the following criteria: ultraviolet and infrared absorption, spectra, chromatographic behavior, melting point, and reactivity in a specific color test. This clue led to the discovery that spf-bearing mice have an abnormal form of liver ornithine ca...

Cell extracts of Methanococcus jannaschii have been shown to readily convert L-ornithine to L-proline. This cyclization reaction proceeds with the loss of only the C-2 nitrogen, as has been documented for ornithine cyclodeaminase (EC 4.3.1.12). Since no gene homologous to that coding for ornithine cyclodeaminase is present in the genome of M. jannaschii, these results indicate that proline bios...